iTelecast through PBX Publishing Technology

  • Technology

  • PBX Technology Platform:

  • PBX Technology Architecture

1. Technology

Live Telecast over Broadband
Live event telecast involves broadcasting an event in real-time over the broadband. The live event telecast process involves a camera for the capturing media, an encoder to digitize the content, a content delivery network to distribute and deliver the content and a publishing platform where the live video signals are made available to potential end-users.

Live telecast events can be viewed by audiences around the world on different types of devices connected to the internet such as laptops, iPads or any Tablet PC, desktops, tablets, mobile phones, TV sets, etc. This capability to reach a much wider audience across a much larger geographic area is one of the most unique and exciting applications of PBX publishing technology.

iTelecast Live Technology
The concept of live telecasting over broadband of a event is not only exciting but also relatively easy to do with the innovating streaming technology developed by Picture Broadcasting Experience –Romania ( www.pbxtelecom.ro) . This technology is based on a computing-cloud that allows on-demand creation of streaming instances. Events are captured live by cameras. The PBX video teleasting engine, Star Media Center SMC takes the video feeds from Video cameras as input, encodes it in industry-standard H.264 and VP6 video codecs, and transmits the stream by a satellite Station/WiMax/EVDO or fix line broadband connection to a computing-cloud. On the cloud, transmission instances are created on-demand and are then broadcast over the cloud. The telecasting instances also archive the event which are later moved to the cloud storage for video archiving.

Telecasting over Cloud Protocol
iTelecast uses Real Time Messaging Protocol (RTMP) which is a protocol for telecasting audio, video and data over the broadband, between a Flash player and a server. iTelecast uses the plain version of the RTMP protocol which works on top of TCP. This protocol maintains persistent connections and allows low-latency communication. To deliver live video signals smoothly and transmit as much information as possible, these signals are split into fragments and their size is negotiated dynamically between the client and server while sometimes it is kept unchanged. Default fragment sizes used are 64-bytes for audio data, and 256 bytes for video data. Fragments from different streams may then be interleaved, and multiplexed over a single connection. In practice, the interleaving and multiplexing is done at the packet level, with RTMP packets across several different active channels being interleaved in such a way as to ensure that each channel meets its bandwidth, latency, and other quality-of-service requirements. Packets interleaved in this fashion are treated as indivisible, and are not interleaved on the fragment level. The publishing platform uses PBX media Player which is the most widely adopted RTMP client. Media Player supports playback of audio and video signal from RTMP servers (when installed as a web browser plug-in).

2. PBX Technology Platform:

Management Server:
Specs: PBX management server can handle users database, billing, PBX VOD server, manages PBX publishing points, backups, software updates, ultra target advertising content filtering module, PBX Content management system, Bandwidth management software, autoalram generator etc

PBX Encoders
Can Telecast over the cloud up to 4 channels simultaneously. Video encoders are responsible for transforming an input video signal that can be of various formats into a digital compressed stream. The video output is either in MPEG–2, MPEG–4 AVC, or WM VC–1. Video encoders can also be responsible to encapsulate the video signals into a transport format that can be an ATM adaptation layer or IP packets. Real-time video encoders that encode live TV feeds used to be very expensive. Most video encoders for live TV are in the national head end; however, they are also present in regional head ends for local programming. The key technical attributes of video encoders are quality of the encoding, compression rate, variety of encoding algorithms and support for statistical multiplexing.

PBX Publishing points:
These Servers are used for distributing the live video signals to the end users. PPS also have the purpose of delivering the stream to the nearest PPS (carriers).

Specs: Each PBX Publishing Point can publish up to 50 channels simultaneously to an unlimited number of concurrent users. Although the number of concurrent users will be decided by the network limitations. The number of maximum concurrent users can be calculated by dividing the available bandwidth to the bitrate of a channel. For example: 1000 mbps / 0,064 mbps = +10,000 concurrent users.

PBX PPS Software: Windows 2003 or Windows 2008, Real VNC license, NOD 32 license, PBX own SDK and tool kits.

PBX Middleware Unit
PBX Middleware is the software and hardware infrastructure that connects the components of an IPTV solution. It is a distributed operating system that runs both on servers at the telco location and on the STBs. Among other things, it performs end-to-end configuration, provisions the video servers, links the electronic program guide (EPG) with the content, acts as a boot server for the PCs and the Set Top Box ( STB) and ensures that all STBs run compatible software. The key technical attributes of a middleware are reliability, scalability, and ability to interface with other systems.

PBX Conditional Access System (CAS) with Digital Rights Management (DRM)
Live Video signal protection : by implementing machine level firewall – when a uplink request is made from the client to the management server, the latter sends a POST message with the IP and MAC of the client to the publishing point (the machine with the live uplink) that will lift the firewall restrictions for that particular client (default all IPs and MACs are blocked). After a period of time (few hours) the firewall rules are reset.

For the communication protocol, a secret algorithm is being used that changes daily (of course, both on the client side and on the server side).

PBX Technology: Encoding & Telecasting

  • At the heart of the PBX service are the live TV capturing and telecasting servers – Star Media Center.

  • Star Media Center is a proprietary software solution based on DirectX and Windows Media Format SDKs.

  • Being an in-house developed solution for telecasting , SMC has been modified and adapted for the express needs of the PBX IPTV service.

  • SMC has been tested since 2003 and it is now a mature product on the market downloaded by millions of people.


SMC Features List:

  • Works directly with DVB receivers or TV-cards

  • The live content is captured at the highest resolution and then deinterlace and denoising filters are applied. On top of these, another special filter is applied (developed in-house) that “formats” the analogical video signals for the compression thus outputting a higher quality even though the same codec is used

  • Each telecasting client is managed separately. The PBX server can change bit rate on the fly if the client can’t maintain a certain internet speed or latency – especially useful with wireless networks

  • Supports latest Windows Media codecs from Microsoft

  • Very low resources required: a normal commercial PC can uplink up to 4 live sessions simultaneously

  • Each SMC instance can stream to an unlimited number of clients

  • Seamless integration with the PBX IPTV management

  • Very high security – no unauthorized client can connect to the live session.

3. PBX Technology Architecture

  • Currently there are two live streaming deployment architectures available:

1) Client – Server. This implies that all clients from everywhere must connect to a single server.

PROS: very secure, very simple to implement

CONS: bandwidth bottle necks will occur with large number of clients connecting at the same time








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